The crew coffee machine (an Electrolux unit) had an issue where a pump solenoid was continuously energised. I opened it and noted that there are three triacs used for switching the heater, pump and possibly a diverter. Although the small TO92 cased triac associated with the running pump was not showing the usual signs of being short circuit, I decided to swap it out anyway. I couldn't find the same triac, but found one with a similar spec. The small TO92 cased triacs seem to be quite commonly used for switching solenoid valves in home appliances like clothes washers.
The new triac did the trick and the unit now runs again.